I-495 Bridge Rehabilitation

Brudis & Associates, Inc. (BAI) was responsible for the complete construction plans, specifications and cost estimates for the bridge rehabilitation and deck replacement of the Forestville Road Bridge over I-95/I-495 in Prince George’s County. The existing structurally obsolete bridge built in 1964, had a sufficiency rating of 75.3 making it eligible for Federal Bridge Rehabilitation funding. The bridge carries one NB lane and one SB lane over I-495 and connects MD 337 on the south to Suitland Parkway to the north with average daily traffic of 11,075 (2007 figure) and has an anticipated average daily traffic of 11,075 by 2030. BAI provided replacement bridge construction in two phases. Services included structural design, maintenance of traffic alternatives analysis, maintenance of traffic, and approach roadways.

Structural Design: BAI provided construction documents for the removal and replacement of the existing bridge deck with the new concrete deck section supported on the existing steel beams, minor repairs to the steel superstructure and concrete abutments, new chain link safety fence, and reconstruction of the abutments and wing walls to support new ADA compliant sidewalks on both sides of the structure. The deck replacement is 8½” concrete slab with a clear roadway width of 32’ between a 34” F-shape parapet on the north and a 5’-8” sidewalk and parapet on the south side. The replacement superstructure width is 40’-5¾” total. The new bridge roadway provides two 12’-0” lanes and two 4’-0” shoulders.

MOTAA/MOT: BAI was responsible for maintenance of traffic alternatives analysis as well as maintenance of traffic plans and services for the two phase bridge construction. The MOTAA involved Synchro/SimTraffic modeling to determine traffic impacts to the surrounding road network which involved seven (7) intersections within the study area. BAI also used MD-QuickZone software to determine total costs (delays, inventory and economic costs) for each of the three proposed MOT options. BAI used the following maintenance of traffic plan: One lane of traffic was maintained across the bridge in the southbound direction only during both construction stages. Temporary concrete traffic barriers were used to separate the traffic lane from the construction area. Northbound traffic was detoured to MD Route 4 (Pennsylvania Avenue) during the construction period. Pedestrian traffic on the bridge was maintained during Stage 1 construction by a temporary sidewalk provided on the north side of the bridge by widening the existing safety curb with temporary concrete. During Stage 2 construction a 3’-1” wide portion of the new bridge deck sidewalk was used for pedestrians.

Emergency Repair and Design Services: During construction, the structure was hit by an over height vehicle and was severely damaged. BAI provided an emergency inspection, details for temporary bracing system, structural analysis and design for new steel girder plate girder using AASHTO ASD, development of girder replacement plans, typical section, girder elevation details, MOT for traffic controls, red-line revisions to the contract documents and construction phase services

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